Kelly Clarkson -- Stuffed Mushrooms ... Key To Singing LIVE

Kelly Clarkson

Stuffed Mushrooms ...

Key To Singing LIVE

1/23/2013 12:40 AM PST BY TMZ STAFF

EXCLUSIVE

Wanna know the secret to Kelly Clarkson's sensational LIVE performance of "My Country, 'Tis of Thee" at the Presidential Inauguration? Two words ... STUFFED MUSHROOMS.

That's right, the night before Kelly rocked the National Mall in front of more than 800,000 people ... she and a few friends carbo-loaded at Buca di Beppo in D.C. -- and as everyone knows by now, it clearly paid off.

HERE'S THE RUNDOWN Meredith Viera Defends the Killer of Cecil the Lion Jennifer Beals in a Hot-Dog-in-Car Controversy A 'Bachelorette' Star Gets Bashed in the Head with a Brick Zayn Malik is Goin' Solo Thanks to Simon Cowell